Please help. English section basic question...

Basic question about comma.

The Sargeats also established a relationship with the famous

suffragist Susan B. Anthony, who (underlined)

was jailed for registering to vote.

Why is the underlined part correct(comma after Anthony)? The rule about comma that I learned is that there should be no comma if the name or title is one of many. There should be a comma between name or title if the name or comma is only one person or thing. Moreover, there should be no comma before who (Always).

Any thoughts?

“who… vote” is a dependent clause. The comma is being used to set off non-essential information. To illustrate a similar idea, think of the sentence… Susan B. Anthony, who was jailed for registering to vote, had a relationship with the Sargeats. In your example, there is an independent clause before the comma followed by a dependent clause after the comma. The dependent clause is not needed for the first part of the sentence to make sense.